EP3401514B1

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Info

Publication number: EP3401514B1
Application number: EP18171660.6A
Authority: EP
Inventors: Todd A. Davis; Denman H. James; Daniel L. Gysling; Joseph D. WALKER
Original assignee: Raytheon Technologies Corp
Current assignee: RTX Corp
Priority date: 2017-05-11
Filing date: 2018-05-09
Publication date: 2021-08-11
Anticipated expiration: 2038-05-09
Also published as: US20180328225A1; EP3401514A1; US10662811B2

Description

BACKGROUND OF THE INVENTION

1. Technical Field

This disclosure relates generally to a gas turbine engine lubrication systems and methods and more particularly to gas turbine engine lubrication systems and methods for use with fluid damping structures.

2. Background Information

Gas turbine engines are often configured to include a fan section, a low pressure compressor section, a high pressure compressor section, a combustor section, a low pressure turbine section, a high pressure turbine section, a low speed spool, and a high speed spool. The fan section may be configured to drive air along a bypass flow path, while the compressor section drives air along a core flow path for compression and communication into the combustor section then expansion through the turbine section. The low speed spool and the high speed spool are mounted for rotation about an engine central longitudinal axis relative to an engine static structure via several bearing systems. The low speed spool generally interconnects the fan section, the low pressure compressor section and the low pressure turbine section. The high speed spool generally interconnects the high pressure compressor section and the high pressure turbine section. The combustor section is disposed between the high pressure compressor section and the high pressure turbine section. The high speed spool may be described as normally rotatable about an axis of rotation.
Under normal operating conditions, a shaft section of a spool (e.g., a shaft section of the high speed spool) will rotate without significant vibration. Under certain operating conditions, however, a spool shaft section may be subject to cyclical, orbital motion (i.e., motion that includes a displacement of the axis of rotation - referred to hereinafter as an "unbalanced condition") that can lead to undesirable vibration. Such cyclical, orbital motion may be the product of temporary thermal bowing of the spool shaft section as a result of a thermal gradient within the engine. Once the thermal gradient sufficiently dissipates, the imbalanced condition dissipates and the spool shaft section restores itself to normal operating condition; e.g., rotation about the axis of rotation.
As will be appreciated by those skilled in the art, the existence of an imbalanced condition in a rotor shaft may result in a greatly increased demand on the bearing components to restrain the movement of the rotor shaft and to transfer the lateral forces induced by the imbalanced condition into the machinery mounting structure.
One method of reducing the aforesaid lateral forces and attendant stresses on the bearings is the use of a fluid damping structure (sometimes referred to as "fluid squeeze damper"). Fluid damper structures are known in the prior art, but many suffer from performance issues and/or require lubricant fluid boost pump mechanisms.
GB 2 033 024 A discloses a prior art damper ring as set forth in the preamble of claim 1.
US 4 669 893 A discloses a prior art annular oil damper arrangement.
JP HI 1 629 53 A discloses a prior art bearing device.
US 5 149 206 A discloses a prior art hydraulic shaft damper pressure control.

SUMMARY OF THE DISCLOSURE

According to an aspect of the present invention, a damper ring is provided as recited in claim 1.
According to any embodiment or aspect of the present invention, the one or more check valve passages may include at least ten check valve passages spaced substantially uniformly in a circumferential direction around the annular body.
According to any embodiment or aspect of the present invention, each check valve passage may extend from the open end to a terminal end disposed within the body.
According to any embodiment or aspect of the present invention, each check valve passage may include a first portion having a diameter D1, a second portion having a diameter D2, and a third portion having a diameter D3, wherein D1 > D2 > D3, and the inlet aperture may extend between the third portion and the outer radial surface, and the outlet aperture may extend between the second portion and the inner radial surface, and the check valve is disposed in the second portion.
According to any embodiment or aspect of the present invention, the at least one fluid stop may include a plug disposed in each check valve passage.
According to any embodiment or aspect of the present invention, at least one of the one or more check valve passages may have a centerline that extends in a direction that is parallel to the axial centerline of the damper ring, and the check valve passage centerline and the axial centerline are co-planar.
According to any embodiment or aspect of the present invention, at least one of the one or more check valve passages may have a centerline that extends in a direction that is skewed by an angle α to the axial centerline of the damper ring, and the check valve passage centerline and the axial centerline are non-co-planar.
According to any embodiment or aspect of the present invention, the fluid check valve may be a fluid-impedance check valve with no moving components.
According to an aspect of the present invention, a gas turbine engine is provided as recited in claim 9.
According to any embodiment or aspect of the present invention, each check valve passage may extend from the open end to a terminal end disposed within the body.
According to any embodiment or aspect of the present invention, the at least one fluid stop may include a plug disposed in each check valve passage.
According to any embodiment or aspect of the present invention, at least one of the one or more check valve passages may have a centerline that extends in a direction that is parallel to the axial centerline of the damper ring, and the check valve passage centerline and the axial centerline are co-planar.
According to any embodiment or aspect of the present invention, at least one of the one or more check valve passages may have a centerline that extends in a direction that is skewed by an angle α to the axial centerline of the damper ring, and the check valve passage centerline and the axial centerline are non-co-planar.
According to any embodiment or aspect of the present invention, the fluid check valve may be a fluid-impedance check valve with no moving components.
According to an aspect of the present invention, a method of providing a damping fluid within a fluid damping structure disposed within a gas turbine engine, wherein the gas turbine engine includes a rotor shaft, is provided as recited in claim 10.
The foregoing features and the operation of the present invention will become more apparent in light of the following description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic partially sectioned view of a gas turbine engine.
FIG. 2 is a diagrammatic cross-sectional view of a portion of a gas turbine engine, showing a fluid damping structure.
FIG. 3 is a perspective view of a damper ring embodiment.
FIG. 4 is a perspective view of a damper ring embodiment.
FIG. 5A is a side view of the damper ring embodiment shown inFIG. 4.
FIG. 5B is a planar view of the damper ring embodiment shown inFIG. 4.
FIG. 6 is a diagrammatic sectional partial view of a damper ring embodiment.
FIG. 7 is a diagrammatic sectional partial view of a damper ring embodiment.

DETAILED DESCRIPTION

It is noted that various connections are set forth between elements in the following description and in the drawings (the contents of which are included in this disclosure by way of reference). It is noted that these connections are general and, unless specified otherwise, may be direct or indirect and that this specification is not intended to be limiting in this respect. A coupling between two or more entities may refer to a direct connection or an indirect connection. An indirect connection may incorporate one or more intervening entities.
Referring now to the FIGURES, to facilitate the description of the present disclosure a two-spool turbofan typegas turbine engine 20 is shown (e.g., seeFIG. 1). This exemplary embodiment of a gas turbine engine includes afan section 22, acompressor section 24, acombustor section 26, aturbine section 28, and a main lubrication system in fluid communication with one or more fluid damping structures. Thefan section 22 drives air along a bypass flow path B in a bypass duct, while thecompressor section 24 drives air along a core flow path C for compression and communication into thecombustor section 26 then expansion through theturbine section 28. Although a two-spool turbofan gas turbine engine is described herein to facilitate the description of the present disclosure, it should be understood that the present disclosure is not limited to use with two-spool turbofans as the teachings may be applied to other types of turbine engines; e.g., three-spool architectures.
Theexemplary engine 20 shown inFIG. 1 includes alow speed spool 30 and ahigh speed spool 32 mounted for rotation about an engine central longitudinal axis A relative to an enginestatic structure 36 viaseveral bearing systems 38. It should be understood that the location, number, and characteristics ofbearing systems 38 may vary to suit the particular application.
Thelow speed spool 30 generally includes aninner shaft 40 that interconnects afan 42, alow pressure compressor 44 and alow pressure turbine 46. Theinner shaft 40 is connected to thefan 42 through a speed change mechanism, which in exemplarygas turbine engine 20 is illustrated as a gearedarchitecture 48 to drive thefan 42 at a lower speed than thelow speed spool 30. Thehigh speed spool 32 includes anouter shaft 50 that interconnects ahigh pressure compressor 52 andhigh pressure turbine 54. Acombustor 56 is arranged inexemplary gas turbine 20 between thehigh pressure compressor 52 and thehigh pressure turbine 54. Theinner shaft 40 and theouter shaft 50 are concentric and rotate via bearingsystems 38 about the engine central longitudinal axis "A" which is collinear with their longitudinal axes.
The core airflow is compressed by thelow pressure compressor 44 then thehigh pressure compressor 52, mixed and burned with fuel in thecombustor 56, then expanded over thehigh pressure turbine 54 andlow pressure turbine 46. Theturbines 46, 54 rotationally drive the respectivelow speed spool 30 andhigh speed spool 32 in response to the expansion. It will be appreciated that each of the positions of thefan section 22,compressor section 24,combustor section 26,turbine section 28, and gearedarchitecture 48 may be varied. For example, gearedarchitecture 48 may be located aft ofcombustor section 26 or even aft ofturbine section 28, andfan section 22 may be positioned forward or aft of the location of gearedarchitecture 48.
Thegas turbine engine 20 diagrammatically depicted inFIG. 1 is one example of a high-bypass geared aircraft engine. In other examples, thegas turbine engine 20 may have a bypass ratio that is greater than about six (6), with an example embodiment being greater than about ten (10), the gearedarchitecture 48 may be an epicyclic gear train, such as a planetary gear system or other gear system, with a gear reduction ratio of greater than about 2.3 and thelow pressure turbine 46 may have a pressure ratio that is greater than about five. In one disclosed embodiment, the gas turbine engine bypass ratio is greater than about ten (10:1), the fan diameter is significantly larger than that of thelow pressure compressor 44, and thelow pressure turbine 46 has a pressure ratio that is greater than about five (5:1). Thelow pressure turbine 46 pressure ratio is pressure measured prior to inlet oflow pressure turbine 46 as related to the pressure at the outlet of thelow pressure turbine 46 prior to an exhaust nozzle. The gearedarchitecture 48 may be an epicycle gear train, such as a planetary gear system or other gear system, with a gear reduction ratio of greater than about 2.3:1. It should be understood, however, that the above parameters are only exemplary of one or more embodiments of a geared architecture engine and that the present disclosure is applicable to other gas turbine engines including direct drive turbofans.
Referring now toFIG. 2, embodiments of the present invention include adamper ring 62, afluid damping structure 64, and a method for providing a damping fluid (e.g., a lubricant fluid used within the engine 20) to afluid damping structure 64. Embodiments of thepresent damper ring 62 can be used in a variety of differentfluid damping structure 64 configurations, and the present disclosure is not therefore limited to aparticular damper ring 62 configuration, or a particularfluid damping structure 64. Thefluid damping structure 64 is typically, but not necessarily, disposed radially adjacent abearing 66 for arotor shaft 68 of agas turbine engine 20; e.g., a high speed spool of a turbofan type gas turbine engine.
Theengine rotor shaft 68 is rotatable about an axis "AR" within a range of rotational velocities. Thebearing 66 includes a plurality of rollingelements 70 disposed between aninner race 72 and anouter race 74. Typically, theinner race 72 is engaged with therotor shaft 68, and rotates with therotor shaft 68 during operation of thegas turbine engine 20. Theouter race 74 is non-rotationally mounted to abearing support 76. The rollingelements 70 are configured for rotational movement between the inner and outer bearing races 72, 74. The present disclosure is not limited to use with any particular type of bearing or any particular bearing support configuration unless otherwise provided below.
FIG. 2 shows an embodiment wherein the outer race of thebearing 66 is engaged with astatic bearing support 76. The term "static" as used here indicates that the bearingsupport 76 is non-rotational. The bearingsupport 76 may be configured to move (e.g., radial deflection) in response to a displacement of the axis of rotation of therotor shaft 68 with which thebearing 66 is associated. The bearingsupport 76 includes a circumferentially extending firstradial surface 78 and secondradial surface 80. InFIG. 2, the firstradial surface 78 and the secondradial surface 80 are on opposing sides of a portion of the bearingsupport 76, but this is not required. The firstradial surface 78 is engaged with theouter bearing race 74. The secondradial surface 80 defines a part of thefluid damping structure 64. In alternative embodiments, the bearingsupport 76 may be engaged with, but independent of, thefluid damping structure 64; e.g., the bearingsupport 76 may not define a part of thefluid damping structure 64.
Thefluid damping structure 64 is further defined by thedamper ring 62 and a pair of ring seals 82. Collectively, thedamper ring 62, the ring seals 82, and the bearing support 76 (or other element if thedamper support 76 is independent of the fluid damping structure 64) define a dampingchamber 84 configured to receive a damping fluid. The ring seals 82 are spaced axially apart from one another and extend circumferentially about the axis of therotor shaft 68. Eachring seal 82 extends radially between and engages the bearingsupport 76 and thedamper ring 62 to define a portion of the dampingchamber 84. In the embodiment shown inFIG. 2, the bearingsupport 76 includes a pair ofannular slots 86 disposed within the secondradial surface 80, each configured to receive a portion of aring seal 82. The present invention is not limited to any particular structure for locating and/or retaining the ring seals 82; e.g., thedamper ring 62 may include annual slots for locating and/or retaining the ring seals 82. The ring seals 82 may be configured to create a fluid tight between the bearingsupport 76 and thedamper ring 62, or to permit some amount of fluid leakage from thefluid damping structure 64. In some embodiments, thefluid damping structure 64 may include one or more fluid vents (not shown) that permit fluid to exit thefluid damping structure 64.
Referring now toFIGS. 3-6, thedamper ring 62 has afirst end surface 88, asecond end surface 90, an outerradial surface 92, and an innerradial surface 94 that collectively define an annular ring type configuration that extends circumferentially around anaxial centerline 96. Theaxial length 98 of thedamper ring 62 may be defined at the distance between the first and second end surfaces 88, 90 at a given radial distance from the axial centerline 96 (e.g., SeeFIG. 5A). The innerradial surface 94 is disposed radially inside of the outerradial surface 92 relative to theaxial centerline 96. Theradial thickness 100 of thedamper ring 62 may be defined as the distance between the inner and outer radial surfaces 94, 92 at a given position on theaxial centerline 96. Thethickness 100 of thedamper ring 62 may be uniform along substantially the entireaxial length 98 of thedamper ring 62, but that is not required. Thedamper ring 62 embodiment shown inFIG. 5B, for example, has auniform thickness 100 along substantially the entireaxial length 98 of thering 62 but also includes alip 102 disposed adjacent thesecond end surface 90. Hence, this embodiment of thedamper ring 62 does not have auniform thickness 100 along its entireaxial length 98.
Thedamper ring 62 includes one or morecheck valve passages 104 extending within the body of thering 62. In the embodiments shown inFIGS. 3-6, eachcheck valve passage 104 extends axially from thefirst end surface 88 inwardly toward thesecond end surface 90, between the inner and outer radial surfaces 94, 92, but does not extend entirely between the first and second end surfaces 88, 90. In these embodiments, eachcheck valve passage 104 may be described as having a firstopen end 106 disposed at thefirst end surface 88 and a second terminal end 108 (e.g., seeFIG. 6). In alternative embodiments, acheck valve passage 104 may extend entirely between the first and second end surfaces 88, 90 (e.g., seeFIG. 7).
In some embodiments, as can be seen inFIG. 3, thecheck valve passages 104 may extend substantially in an axial lengthwise direction; e.g., having acenterline 110 that extends in a direction that is parallel to theaxial centerline 96 of thedamper ring 62, and the twocenterlines 96, 110 may be described as being co-planar. In other embodiments, as can be seen inFIGS. 4,5A, and 5B one or more of thecheck valve passages 104 may have acenterline 110 that extends in a direction that is skewed relative to thecenterline 96 of thedamper ring 62; e.g., thecheck valve passage 104 extends along acenterline 110 that deviates circumferentially relative to theaxial centerline 96 of thedamper ring 62, and the centerlines are therefore not co-planar. The embodiment shown inFIGS. 4,5A, and 5B shows thecheck valve passage 104centerline 110 skewed at an angle of "α" to theaxial centerline 96 of thedamper ring 62. Acheck valve passage 104 having acenterline 110 that is skewed relative to thecenterline 96 of thedamper ring 62 may be configured to have a greater passage length (e.g., the distance between theopen end 106 of thepassage 104 and theterminal end 108 of the passage 104), than would be possible with acheck valve passage 104 that extends substantially in an axial lengthwise direction. The greater passage length permits the use of longer length check valves.
Eachcheck valve passage 104 is in fluid communication with the outerradial surface 92 of thedamper ring 62 by aninlet aperture 112 that extends between the outerradial surface 92 and thecheck valve passage 104. Eachcheck valve passage 104 is in fluid communication with the innerradial surface 94 of thedamper ring 62 by anoutlet aperture 114 that extends between the innerradial surface 94 and thecheck valve passage 104. As will be described below, eachcheck valve passage 104 may include a plurality of different diameters. For example, thecheck valve passage 104 embodiment shown inFIG. 6 includes afirst portion 116 having a diameter D1, asecond portion 118 having a diameter D2, and athird portion 120 having a diameter D3, where D1 > D2 > D3. The present disclosure is not limited to this particular configuration.
Thedamper ring 62 includes acheck valve 122 disposed in eachcheck valve passage 104, typically between theinlet aperture 112 and theoutlet aperture 114. Thecheck valve 122 is configured to permit fluid flow through thecheck valve 122 in a first direction (e.g., as shown inFIG. 6), and to not permit fluid flow through thecheck valve 122 in a second direction, opposite to the first direction. The terms "to permit flow" and "to not permit flow" as used herein are not intended to be interpreted in absolute terms. For example, when acheck valve 122 "permits" fluid flow in a first direction, the fluid flow may be subjected to some amount of head loss (e.g., frictional losses, minor losses, etc.) between the point of entry and the point of exit of the check valve, but in terms of magnitude, the amount of head loss is minimal when compared to the fluid flow through thecheck valve 122 in the first direction. In contrast, when acheck valve 122 "does not permit" fluid flow in a second direction (opposite the first direction), the check valve prevents substantially any fluid flow from traveling through the check valve in the second direction. Some leakage through thecheck valve 122 may occur in the second direction, but the amount of leakage is minimal when compared to the fluid flow through thecheck valve 122 in the first direction. Thecheck valve 122 is oriented within thecheck valve passage 104 such that fluid entering thecheck valve passage 104 via theinlet aperture 112 must pass through thecheck valve 122 before reaching theoutlet aperture 114. Thecheck valve 122 is also oriented within thecheck valve passage 104 such that fluid in thecheck valve passage 104 adjacent theoutlet aperture 114 is prevented from passing entirely through thecheck valve 122 in a direction toward the inlet aperture 112 (other than an acceptable leakage as described above).Acceptable check valves 122 are configured to operate for the fluid pressures of the application at hand; i.e., configured to open when subjected to a fluid pressure at or above a predetermined minimum inlet fluid pressure and permit fluid flow through the valve with an acceptable amount of head loss, and to prevent fluid flow in the opposite direction up to a predetermined fluid pressure.
An example of an acceptable check valve is one that is fluid operated and does not require moving parts. The term "fluid-impedance check valve" as used herein describes a device having internal fluid paths between a first end (i.e., the inlet) and a second end (i.e., the exit) of the valve. The internal fluid paths permit fluid flow through the check valve between the inlet end toward the exit end. The same internal fluid paths substantially impede fluid flow attempting to pass through the check valve in the opposite direction, from the exit end toward the inlet end. For example, the internal fluid paths may be configured so orient opposing fluid flows, etc. The fluid-impedance check valve does not utilize moving mechanical components (e.g., a ball/ball seat, a deflectable reed, etc.) to directionally permit or impede fluid flow through the device, but rather uses the fluid flow itself to create the directional characteristics. In some embodiments, a fluid-impedance check valve may be formed integrally within acheck valve passage 104. In other embodiments, a fluid-impedance check valve may be a self-contained unit that is disposed within acheck valve passage 104.
In a gas turbine engine that is operating under "normal" conditions (e.g., in a constant RPM cruise mode), the fluid pressure within thefluid damping structure 64 is substantially consistent. In an imbalanced condition, however, a spool shaft section may be subject to cyclical, orbital motion (sometimes referred to as a "whirl"), which motion can create variations in fluid pressure within the damping chamber 84 (i.e., a dynamic pressure component). Generally speaking, an increase in the "whirl" causes a commensurate increase in the dynamic pressure component of the fluid within the dampingchamber 84. Fluid pressure variations (both negative and positive) can be high in magnitude and short in duration. Our understanding is that fluid-impedance check valves perform well when subjected to such variations. In addition, it is our understanding that because fluid-impedance check valves of the type described herein do not include any mechanical moving parts, they also provide favorable durability when used in the present application.
Another example of an acceptable check valve is an axial type check valve such as those manufactured by The Lee Company of Westbrook, Connecticut, USA. The present disclosure is not, however, limited to any particular type ofcheck valve 122.
Thedamper ring 62 further includes a fluid stop to prevent fluid exiting thefirst end surface 88 of thedamper ring 62; e.g., aplug 124 or other structure disposed within eachcheck valve passage 104. For example, aplug 124 may be disposed within thecheck valve passage 104 at a position between thefirst end surface 88 and theoutlet aperture 114. In this position, theplug 124 does not impede fluid flow exiting thedamper ring 62 through theoutlet aperture 114, but does prevent fluid flow exiting thecheck valve passage 104 through thefirst end surface 88. The present disclosure is not limited to any particular type of fluid stop structure functionally able to prevent fluid flow exiting thecheck valve passage 104 through thefirst end surface 88; e.g., another example of a fluid stop is a seal plate attached to thefirst end surface 88. In the embodiment shown inFIG. 6, thecheck valve 122 is positioned in thesecond portion 118 of thecheck valve passage 104 against a shoulder at the intersection of the first andsecond portions 116, 118 of thecheck valve passage 104, and a fluid stop in the form of aplug 124 is press-fit within thefirst portion 116 of thecheck valve passage 104 at the intersection of the first andsecond portions 116, 118 of thecheck valve passage 104. The differences in portion diameters (D1, D2, D3) of thecheck valve passage 104 facilitate the positioning of thecheck valve 122 and theplug 124 within thecheck valve passage 104.
As indicated above, in some embodiments, thecheck valve passages 104 may extend between the first and second end surfaces 88, 90 (e.g., seeFIG. 7). Extending thecheck valve passages 104 between the first and second end surfaces 88, 90 may in some instances facilitate the manufacturing of thedamper ring 62. In these embodiments, thedamper ring 62 may include asecond plug 126 or other structure (similar to that described above) configured to prevent fluid flow from exiting thedamper ring 62 through thesecond end surface 90.
Thedamper ring 62 is configured to be disposed in communication with anannular supply cavity 128. Specifically, thedamper ring 62 is configured such that theinlet apertures 112 are in fluid communication with theannular supply cavity 128. Theannular supply cavity 128 may be a single circumferentially extending annular cavity, or it may include a plurality of annular sections with each section in fluid communication with a plurality ofinlet apertures 112 and therefore checkvalve passages 104. For example,FIG. 2 shows the outerradial surface 92 of thedamper ring 62 in contact with anannular support structure 130. A slot disposed in theannular support structure 130 forms theannular supply cavity 128. One ormore passages 132 extending through thesupport structure 130 permit lubricant fluid to pass into theannular supply cavity 128, and thereafter into thecheck valve passages 104 of thedamper ring 62 via therespective inlet apertures 112.
The above-described configurations of the damper ring that include one or morecheck valve passages 104 extending axially from thefirst end surface 88 inwardly toward thesecond end surface 90, between the inner and outer radial surfaces 94, 92, are particularly well suited to those embodiments that include fluid-impedance check valve. In some applications, fluid-impedance check valves may have a relatively long axial length (i.e., the distance from the inlet of the valve to the exit of the valve). Embodiments of the present damper ring have an axial length that is substantially longer than radial width of the body portion containing the check valve passage. As a result, the damper ring is able to accommodate longer length check valves than would be possible if the check valve was oriented radially, and therefore configurable to accept fluid-impedance check valves; i.e., a check-valve with no moving parts and increased durability.
Damping fluid for thefluid damping structure 64 may be provided from themain lubrication system 134 of thegas turbine engine 20. A variety of different gas turbine engine lubricant fluids are known in the public and will not therefore be discussed further herein. The present disclosure is not limited to use with any particular gas turbine engine lubricant fluid. Typical lubricant fluids used within agas turbine engine 20 have a viscosity in the range of about 25 to 1.5 centistokes (25 to 1.5 mm²/_s) within the typical engine operating temperature range.
Themain lubrication system 134 typically includes a main supply pump 136 (e.g., a positive displacement pump). In manygas turbine engines 20, themain supply pump 136 is configured to produce lubricant fluid output at parameters that vary as a function of the rotational speed of a rotor shaft directly or indirectly powering themain supply pump 136. For example, in manygas turbine engines 20, themain supply pump 136 may be mechanically driven off of the high speed spool that connects the high pressure compressor section and the high pressure turbine section. Because themain supply pump 136 is operatively linked to the high speed spool in these embodiments, the output parameters of the main supply pump 136 (e.g., lubricant fluid pressure and flow rate) vary as a function of the rotational speed of the high speed spool.
Under certain gas turbine engine operating conditions (e.g., when theengine 20 is operating in a cruise mode powering an aircraft), the high speed spool is typically rotating in the range of 13,000 to 23,000 revolutions per minute ("rpms"). Hence, amain supply pump 136 sized to meet the engine's lubrication requirements in that operational range would meet the lubricant fluid flow requirements of theengine 20, including those requirements associated with afluid damping structure 64. However,gas turbine engines 20 also operate outside of the aforesaid operational range under certain conditions (e.g., start-up, idle, etc.). Thefluid damping structures 64 must, therefore, be configured to operate under all anticipated engine operating conditions.
Thepresent damper ring 62 is configured to supply an adequate lubricant fluid flow to thefluid damping structure 64 under all engine operating conditions, including those where therespective rotor shaft 68 is operating in an imbalanced condition. The utilization of acheck valve 122 within each of thecheck valve passages 104 operates to maintain the aforesaid lubricant fluid distribution, flow, and pressure within the dampingchamber 84 during an imbalance condition. Hence, the present invention includes a method of fluid damping a bearing compartment within agas turbine engine 20 utilizing afluid damping structure 64 as described above.
While various embodiments of the present invention have been disclosed, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the present disclosure. For example, the present disclosure as described herein includes several aspects and embodiments that include particular features. Although these features may be described individually, it is within the scope of the present invention that some or all of these features may be combined with any one of the aspects and remain within the scope of the present invention. Accordingly, the present invention is not to be restricted except in light of the attached claims.

Claims

A damper ring (62), comprising:
an annular body that extends circumferentially around an axial centerline (96), the body defined by a first end surface (88), a second end surface (90), an outer radial surface (92), and an inner radial surface (94), wherein the outer radial surface (92) and the inner radial surface (94) extend axially from the first end surface (88) toward the second end surface (90), wherein the annular body includes one or more check valve passages (104), each passage (104) extending axially from an open end (106) disposed at the first end surface (88) inwardly toward the second end surface (90), and disposed between the inner radial surface (94) and the outer radial surface (92); and wherein an inlet aperture (112) extends between each check valve passage (104) and the outer radial surface (92) providing fluid communication therebetween
a fluid check valve (122) disposed in each check valve passage (104),
characterised in that: an outlet aperture (114) extends between each check valve passage (104) and the inner radial surface (94) providing fluid communication therebetween;
the fluid check valve (122) is configured to permit fluid flow in a first direction through the check valve passage (104) from the inlet aperture (112) to the outlet aperture (114) and to substantially prevent fluid flow in a second direction opposite the first direction; and
at least one fluid stop (124) configured to prevent fluid exit from the open end (106) of each check valve passage (104).
The damper ring (62) of claim 1, wherein the one or more check valve passages (104) includes at least ten check valve passages (104) spaced substantially uniformly in a circumferential direction around the annular body.
The damper ring (62) of claim 1 or 2, wherein each check valve passage (104) extends from the open end (106) to a terminal end (108) disposed within the body.
The damper ring (62) of any preceding claim, wherein each check valve passage (104) includes a first portion (116) having a diameter D1, a second portion (118) having a diameter D2, and a third portion (120) having a diameter D3, wherein D1 > D2 > D3, and wherein the inlet aperture (112) extends between the third portion (120) and the outer radial surface (92), and the outlet aperture (114) extends between the second portion (118) and the inner radial surface (94), and the check valve (122) is disposed in the second portion (118).
The damper ring (62) of any preceding claim, wherein the at least one fluid stop (124) includes a plug (124) disposed in each check valve passage (104).
The damper ring (62) of any preceding claim, wherein at least one of the one or more check valve passages (104) has a centerline (110) that extends in a direction that is parallel to the axial centerline (96) of the damper ring (62), and the check valve passage centerline (110) and the axial centerline (96) are co-planar.
The damper ring (62) of any of claims 1 to 5, wherein at least one of the one or more check valve passages (104) has a centerline (110) that extends in a direction that is skewed by an angle α to the axial centerline (96) of the damper ring (62), and the check valve passage centerline (110) and the axial centerline (96) are non-co-planar.
The damper ring (62) of any preceding claim, wherein the fluid check valve (122) is a fluid-impedance check valve (122) with no moving components.
A gas turbine engine (20), comprising:
at least one rotor shaft (40,50,68) extending between a compressor section (24) and a turbine section (28);
at least one bearing compartment disposed to support the rotor shaft (40,50,68), the bearing compartment having at least one bearing (66) and at least one fluid damping structure (64), wherein the fluid damping structure (64) includes a damping chamber defined in part by the damper ring (62) of any preceding claim; and
a lubrication system (134) that includes a main supply pump (136) powered by the rotor shaft (40,50,68), the lubrication system (134) configured to provide a flow of fluid lubricant to the damping chamber through the damper ring (62).
A method of providing a damping fluid within a fluid damping structure (64) disposed within a gas turbine engine (20), wherein the gas turbine engine (20) includes a rotor shaft (40,50,68), the method comprising:
operating a main supply pump (136) of the gas turbine engine (20) to produce a damping fluid flow to a fluid damping structure (64), which fluid damping structure (64) includes a damper ring (62) that defines a portion of a damping chamber, the damper ring (62) including:
an annular body that extends circumferentially around an axial centerline (96), the body defined by a first end surface (88), a second end surface (90), an outer radial surface (92), and an inner radial surface (94), wherein the outer radial surface (92) and the inner radial surface (94) extend axially from the first end surface (88) toward the second end surface (90), the annular body including one or more check valve passages (104), each passage (104) extending axially from an open end (106) disposed at the first end surface (88) inwardly toward the second end surface (90), and disposed between the inner radial surface (94) and the outer radial surface (92), and wherein an inlet aperture (112) extends between each check valve passage (104) and the outer radial surface (92) providing fluid communication therebetween, and wherein an outlet aperture (114) extends between each check valve passage (104) and the inner radial surface (94) providing fluid communication therebetween;
a fluid check valve (122) disposed in each check valve passage (104), wherein the fluid check valve (122) is configured to permit damping fluid flow in a first direction through the check valve passage (104) from the inlet aperture (112) to the outlet aperture (114) and to substantially prevent damping fluid flow in a second direction opposite the first direction; and
at least one fluid stop (124) configured to prevent damping fluid exit from the open end (106) of each check valve passage (104); and
providing the damping fluid flow into the damping chamber through the plurality of check valve passages (104) disposed within the damper ring (62) and the check valve (122) disposed in each respective check valve passage (104).
The method of claim 10, wherein each check valve passage (104) extends from the open end (106) to a terminal end (108) disposed within the body.
The method of claim 10 or 11, wherein at least one of the one or more check valve passages (104) has a centerline (110) that extends in a direction that is parallel to the axial centerline (96) of the damper ring (62), and the check valve passage centerline (110) and the axial centerline (96) are co-planar.
The method of claim 10, 11 or 12, wherein at least one of the one or more check valve passages (104) has a centerline (110) that extends in a direction that is skewed by an angle α to the axial centerline (96) of the damper ring (62), and the check valve passage centerline (110) and the axial centerline (96) are non-co-planar.
The method of any of claims 10-13, wherein the fluid check valve (122) is a fluid-impedance check valve (122) with no moving components.